Circuit breaker



J. H. BURNSIDE, 2D

CIRCUIT BREAKER June 11, 1940. v 2,204,528

Filed March 11, 1937 3 Sheets-Sheet 1 My .1 v 1 21 m a: 63 5.9 6%

INVENTOR. Jamesflflumwdgm 65 ATTORNEYS J n 1940- J. H. BURNSIDE. 2D

CIRCUIT BREAKER 5 Sheets-Shed 2 Filed March 11, 1937 Janiesliflurnszdqfi111,5 ATTORNEYS June 11, 1940.

J. H. BURNSIDE, 2D 2,204,528

CIRCUIT BREAKER Filed March 11, 1957 5 Sheets-Sheet 3 Hi4 A-Hornys.

Patented June 11, 1940 UNITED STATES PATENT OFFICE CIRCUIT BREAKER YorkApplication March 11,

19 Claims.

The present invention relates to circuit breakers and embodies, morespecifically, an improved formv of a circuit breaker of the so-calledplug type wherein the circuit breaker is adapted to be received withinthe standard form of receptacle now in use.

More particularly, the invention relates to the type of circuit breakershown and described in applicant's co-pending application, Serial No.104,895, filed October 9, 1936, for Circuit breaker, and this inventionembodies certain important improvements by means of which the operationof breakers of this type is greatly facilitated.

An object of this invention is to provide a circuit breaker which isnormally urged into an open position and held in closed position by animproved form of holding mechanism which is released by a bi-metalelement, the holding mechanism being of such character as to cause it tohold the movable contact effectively in its closed position, at the sametime permitting only a very slight pressure of the bi-metal element torelease it from its holding position.

A further object of the invention is to provide an improved form ofcircuit breaker wherein the spring which urges the movable contact intoan open position is effectively separated from the contact elements toprevent any injury to the spring by heat generated during operation.

A further object of the invention is to provide a circuit breaker of theabove character having a spring to urge the same normally into an openposition, the mechanism being of such character as to cause this springto cushion the final opening motion of the movable breaker element.

A further object of the invention is to provide a circuit breaker of theabove character wherein an eifective wiping contact is preserved betweena central terminal of the breaker and the adjacent end of a movablecontact-carrying spindle.

A further object of the invention is to provide an improved circuitbreaker of the above character wherein a rotatable member is providedwithin the breaker for carrying the movable breaker contact andeffectively inclosing certain of the breaker elements therein.

A further object of the invention is to provide a circuit breaker havingan improved operating mechanism by means of which the movable breakercontact may be moved into a closed position, such mechanism preventingthe movable contact from being held in a closed position under over-loadconditions.

A further object of the invention is to provide an operatingmechanismfor circuit breakers of 1937, Serial No. 130,262

the above character wherein the movable breaker contact is actuatedthereby by motion of the operating means intermittently in a continuousdirection.

Further objects of theinvention will be apparent as it is described ingreater detail in connection with the accompanying drawings, wherem:

Figure 1 is a View in transverse section, taken on line |l of Figure 3,and looking in the direction of the arrows;

Figure 2 is a view in horizontal section, taken on line 2-2 of Figure 1,and looking in the direction of the arrows;

Figure 3 is a view in horizontal section, taken on line 33 of Figure 1,and looking in the direction of the arrows;

Figure4 is a view similar to Figure 3, showing the rotor in openposition; V

Figure 5 is a View taken on the broken section line 55 of Figure 4;

Figure 6 is a plan view of the device in slightly reduced scale;

Figures 7, 8 and 9 are views in horizontal section taken on the line 4-4of Figure 5 looking in the direction of the arrows, the said figuresshowing the mechanism in ofi, reset and on positions, respectively; 7

Figure 10 is a view in section showing the invention incorporated in anattachment plug.

Referring to the above drawings, a circuit breaker is shown as providedwith a casing having a threaded portion 2i and formed with a partition22. The threaded portion 2| is formed with a chamber 23 and receives athreaded shell 24, which is adapted to be threaded into a suitablesocket or receptacle. A lower cover 25 is provided for the chamber 23and carries a central terminal 26 to which a leaf spring 21 is secured.The leaf spring 21 is reversely bent and formed with a cup-shapedcontact 28.

Within the partition 22 is received a spindle 29, the lower end of whichis formed with a cap which is received within the cup-shaped wiper orcontact 28. A coil spring 3| is secured at one end to the casing portion2| and, at its other end, to the spindle 29, the function of this springbeing to urge the spindle 29 normally into an open circuit position. Inthis connection, it is important to observe that the spring 3| is ofsuch character as to expand against the cylindrical wall of chamber 23when the spindle 29 approaches the final open circuit position, thusproducing an efiective cushioning action upon spindle 29 at such time.

The interior of casing 28 receives a rotatable cylindrical member 32,which is secured to the top of spindle 29 to rotate therewith. Astationary contact 33 is provided in the inner portion of casing 20,this contact being carried by a currentccnduc 'ng member 34 having itslower portion 35 received within, and in electrical contact with, theshell 24. A graphite insert 36 is provided to prevent the destructiveeffect of arcing on the stationary contact 33.

The rotor 32 is formed with an inner chamber 31 and has secured theretoa cover plate 38 which encloses the mechanism within the chamber 31 tothe-top of the spindle 29, which is received within the chamber 31, aconducting plate 39 is secured by means of a screw 40. This conductingplate 39 carries a bi-metal element 4|, the free end of which is formedwith a curved pressure surface 42. A pigtail 43' connects the free endof the bi-metal element 4| with a movable contact 43 which is slidablyreceived in the peripheral wall of the rotor 32. A spring 44 normallyurges the contact 43 outwardly into the position shown in Figure 3, atwhich time the movable contact 43 engages the stationary contact 33. Agraphite insert 45 is carried by the movable contact 43 to cooperatewith the graphite insert 36 in preventing destructive arcing.

In order that the rotor may be held in a circuit-closing position, adetent 46 is slidably mounted therein and cooperates with a recess 41 inthe wall of casing 20. This detent is moved axially by means of a togglemember 48, which is pivoted at 49 to the rotor 32. A spring 58 normallyurges the toggle mechanism and detent into the position shown in Fig. 3,at which time the detent 46 engages the sloping surface 5| of recess 41to prevent the opening of the circuit breaker. A shoulder 52 is providedby the recess 41 to engage the detent 46 and locate the mechanism in theclosed position, as illustrated in Figure 3. It will thus be seen thatan overload condition will cause the bi-metal element 4| to moveoutwardly and cause the pressure surface 42 to engage the toggle jointand release the same to permit the circuit breaker to open. Greataccuracy results in view of the toggle mechanism by means of which arelatively slight force may be used to cause this opening motion,regardless of the friction or other conditions of wear between thedetent 46 and the adjacent casing wall.

The movable contact 43 is provided with a pin 53 which is adapted to beengaged by -a latch 54 which is pivoted at 55 to the rotor 32. A spring56 normally urges the latch into a pin-engaging position and the latchis formed with an upwardly extending arm 51 by means of which it may bereleased, as will be described hereinafter. The casing 28 is formed witha cam track 58 which serves to move the contact 43 inwardly into alatched position, as illustrated in Figure 4. The latch 54 holds theslide contact 43 securely in position so that when it slides past therecess 41 it will not engage the shoulder 52 thereof and thus makefurther rotation of the member 32 impossible.

Extending upwardly from the cover 38 is a central shaft 59, in theperipheral surface of which a groove 60 is formed, the groove beingprovided with a shoulder 6|.- cured to the shaft 59 and is provided witha head 63 upon which a pointer 64 is formed. Rotatably mounted upon thehead 63 is a manually operable disc 65 which preferably is formed withits A pin 62 is se-' periphery lying contiguous to the periphery of thecasing 28. Within the casing 28 a cover 66 is provided, the cover beingformed with an upwardly projecting circular flange 61 having serrations68 formed on its inner periphery. The manually operable member 65 isformed with a leaf spring 69 which is adapted to engage the serrations68 and thus permit rotation of the member 65 in one direction only,(clockwise, as illustrated in Figure 8) Motion is transmitted betweenthe member 65 and shaft 59 by means of a disc 18 which is pivoted at 1|to the under-side of the member 65. This disc is provided with acounter-clockwise bias by means of a spring 12 and is formed with an arm13 which is adapted to engage the shoulder 6|. A second arm 14 is formedon the disc 10 and is pivotally connected to a toggle lever 15, theother end of which is pivoted at 16 to the lower side of the member 65.The central pivot 11 of the toggle member 15 extends downwardly and isadapted to engage a cam 18 having an inclined face 19 and a circularface 80. The cam 18 is formed upon the cover 66, as illustrated inFigure 5, and the toggle lever 15 is biased in the position shown inFigure 8 by means of a spring 8|. In this fashion, as illustrated inFigure 8, rotation of the member 65 causes arm 13 to transmit the motionof the member 65 to the shaft 59, thus turning the rotor 32. The cam 16lies in the path of pin 11 to eifect a sequence of operations to bedescribed hereinafter.

Also formed upon the member 65 and depending downwardly therefrom is atrip member 82 which is adapted to engage the arm 51 to release thelatch 54 and brush 43 on the toggle lever 48 in order that the rotor 32may be manually released.

Upon the member 65 is mounted a plate 84, being suitably secured to themember in such fashion as to prevent relative rotation with respectthereto. Plate 84 is provided with suitable indicia which have hereinbeen indicated at 85, 86, 81 and 88.

In operation, and in the position illustrated in Figures '1 and 3, thecircuit breaker is in its closed position, at which time pointer 64points to indicia 86 (on). When excess current flows through thebi-metallic arm 4|, its pressure surface 42 moves the pin 83 on thetoggle 48 outwardly, thus releasing the detent 46 and breaking thecontacts 43 and 36. The tension in spring 3| causes the rotatable member32- to rotate to the position shown in Figure 4, in which contact 43 isapproximately 180 away from the position shown in Figure 3. During therotation of the member 32, the contact 43 is moved inwardly by the camsurface 58 of the casing 28, until the latch 54 engages the pin 53.

To reset the circuit breaker, the member 65 is rotated in a clockwisedirection. Such rotation of the member 65 causes the pin 11 to ride offthe cam 18, at which time the toggle 15 assumes its normal position andthe arm 13 engages shoulder 6|. Further rotation of the member 65 movesthe rotor 32, eventually bringing the detent 46 into engagement with therecess 41, at which time the pointer 64 points to indicia 85 (reset).This last position is shown in Figure 9. The circuit, however, is stillnot closed since the latch 54 has not been released to allow the contact43 to rest against contact 36. This operation is accomplished by furtherrotation of the member 65 so that the cam surface of the stop 82 willengage the arm 51, thus moving it radially outwardly and releasing thelatch 54. At this point the pointer 64 points to indlcia 86 (on). Thecircuit breaker is now in the normal operating position and may betripped by an overload, as described above.

The circuit may also be tripped manually by rotation of the member 65beyond the on position. Such rotation causes the stop 82 to engage thepin 83 on the toggle 49, moving itoutwardly and thus releasing thedetent 46 and breaking the circuit as described above.

In Figures 7, 8 and 9, the arrow found within the outline of the shaft59 indicates the relative position of the movable contact 43. The arrowoutside of the member 65 and at the bottom of the figures indicates therelative position of the stationary contact 33. From Figures 7, 8 and 9,it will be observed that the toggle and 8| and the plate 10 serve as thedriving connection between the manually operable member 65 and the shaft59. When the toggle 80 is in the position shown in Figures 7 and 8, thearm 13 on the plate 19 engages the adjacent shoulder on the shaft 59forming the end of the cut-away portion 60. Turning the member 65 thuscauses the shaft 59 to be turned and. such driving connection ismaintained until the pin 11 at the mid point of the toggle 80 rides upon the cam 18 as illustrated in Figure 9. This results in breaking ofthe toggle and the aforesaid driving connection. The point at whichthisbreak occurs will be apparent from Figure 8 in which position the pin isjust beginning to ride up on the surface of the cam. When the toggle isbroken as illustrated 'at Figure 9, the manually operable member 65 hasno driving or holding connection with the shaft 59 and the free trippingmechanism is thus unaffected by the member 65.

A further feature of the invention resides in the adaptation of acircuit breaker of the type above described for use in connection withan attachment cord. This is illustrated in Figure 10 wherein the prongsof an attachment plug 9|] are illustrated at 9| and 92. Prong 9| isformed with a central terminal 93 with which the contact 26 engageswhile the ,prong 92 is connected to one wire 94 of an attachment cord95. The attachment cord may be carried by the plug by means of athreaded cap 96, the other wire 91 of the cord being soldered to theshell 24. A screw or other fastening element 98 may be provided tosecure the casing 20 to the plug 90, recesses 99 and Hill being providedin order that the various elements may be countersunk within the plugand covered over by a suitable wax or other sealing element.

I claim:

1. A circuit breaker comprising a stationary and a rotatable contact, arotatable spindle upon which the rotatable contact is secured, bi-metalcontrolled means to hold the rotatable contact in closed position,actuating means to move the rotatable contact into a circuit-closingposition, a casing to enclose the contacts, a partition in the casingupon one side of which the contacts are disposed, said spindle beingjournalled in the partition, and a spring on the other side of thepartition to urge the rotatable contact normally into an open position.

2. A circuit breaker comprising a stationary and a rotatable contact, arotatable spindle upon which the rotatable contact is secured, bi-metalcontrolled means to hold the rotatable contact in closed position,actuating means to move the rotatable contact into a circuit-closingposition, a

casing to enclose the contacts, a partition in the casing upon one sideof which the contacts are disposed, said spindle being journalled in thepartition, a spring on the other side of the partition to urge therotatable contact normally into an open position, a terminal in thecasing on the last-named side of the partition, and a wiping contactbetween the terminal and the adjacent end of the spindle.

3. In a circuit breaker, the combination of a fixed contact, a rotatablecontact, manual means for moving the rotatable contact into closedcircuit position, a spring normally urging the rotat' able contact intothe open circuit position, bimetal controlled means for holding therotatable contact releasably in the closed circuit position, a springnormally urging the rotatable contact into engagement with the fixedcontact in the closed circuit position, latching means for holding thesaid rotatable contact releasably out of engagement with said fixedcontact, and means for moving said rotatable contact into the latchedposition as the rotatable contact moves from the closed to the opencircuit position.

4. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing, means to urge the member normally into an openposition, means to move the member into a circuit closing position, adetent to hold the member in circuit-closing position, toggle mechanismto move the detent to a holding position, and means to engage the togglemechanism to release the detent.

5. A circuit breaker comprising a casing, a rotatable control-carryingmember in the casing, means to urge the member normally into an openposition, means to move the member into a circuit-closing position, adetent on the member to hold the member in circuit-closing position,toggle mechanism to move the detent to a holding position, and means toengage the toggle mechanism to release the detent.

6. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing, means to urge the member normally into an openposition, means to move themember into a circuit-closing position, adetent to hold the member in circuit-closing position, toggle mechanismto move the detent to a holding position, and bimetal means to engagethe toggle mechanism to release the detent.

'7. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing, means to urge the member normally into an openposition, means to move the member into a circuit-closing position,toggle mechanism to move the detent to a holding position, a shoulder onthe casing to be engaged by the detent and stop the member incircuit-closing position, and means to engage the toggle mechanism torelease the detent.

8. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the easing, means to urge the member normally into an openposition, releasable means to hold the member in a circuit-closingposition, a manually operable member, means movably mounted on themanual member to engage and move the rotatable member, and means to movethe engaging means to prevent movement of the rotatable member thereby.

9. A circuit breaker comprising a casing, a. rotatable contact-carryingmember in the easing, means to urge the member normally into an openposition, releasable means to hold the mmber in a circuit-closingposition, a manually operable member, a disc pivotally mounted on themanual member and having means thereon to engage the rotatable member,means to maintain the disc in engaging position, and means to render thelast-named means ineffective to hold the disc in engaging position.

10. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing, means to urge the member normally into an openposition, releasable means to hold the member in a circuit-closingposition, a manually operable member, a disc pivotally mounted on themanual member and having means thereon to engage the rotatable member,toggle means to maintain the disc in engaging position, and means torender the last-named means ineffective to hold the disc in engagingposition.

11. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing, means to urge the member normally into an openposition, releasable means to hold the member in a circuit closingposition, a manually operable member, a disc pivotally mounted on themanual member and having means thereon to engage the rotatable member,toggle means to maintain the disc in engaging position, and a cam torender the toggle means ineffective to hold the disc in engagingposition.

12. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing, means to urge the member normally into an Openposition, releasable means to hold the member in a circuit-closingposition, a manually operable member, a disc 'pivotally mounted on themanual member and having means thereon to engage the rotatable member,toggle means to maintain the disc in engaging position, means to biasthe toggle means and disc in an engaging position, and a cam to renderthe toggle means ineffective to hold the disc in engaging position.

13. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing, means to urge the member normally into an openposition, releasable means to hold the member in a circuit-closingposition, a manually operable member mounted coaxially of the saidrotatable member, means mounted movably on the manual member to engageand move the rotatable member, and a trip member on the, manual memberto engage the releasable means.

14. A circuit breaker comprising a casing, a rotatablecontact-carryingmember in the casing, means to urge the member normally into anopenposition, releasable means to hold the member in a circuit-closingposition, a manually operable member mounted coaxially of the saidrotatable member, means mounted movably on the manual member to engageand move the rotatable member, and a trip member on the manual member toengage the releasable means to hold the contact in an open position.

15. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the easing, means to urge the member normally into an openposition, releasable means to hold the member in a circuit-closingposition, a manually operable member means movably mounted on the manualmember to engage and move the rotatable member, and means to permitmotion of the manually operable member in one direction only.

16. A circuit breaker comprising a casing, a rotatable contact-carryingmember in the casing means to urge the member normally into an openposition, releasable means to hold the member in a circuit-closingposition, a manually operable member means movably mounted on the manualmember to engage and move the rotatable member indicating means on themanually operable member, and cooperating indicating means on therotatable member for indicating the actual position of the contacts.

17. In a circuit breaker, a support having a fixed contact thereon, arotor journaled on the support having a contact thereon, a spring continually urging the rotor to contact disengaging position when thecontacts are engaged, a rotatable actuator for moving the rotor tocontact engaging position, means mounted on the rotor and cooperatingwith the said support to hold the rotor in contact engaging position,and an excess current actuated element for releasing the said lastmentioned means whereby the spring moves the rotor to contactdisengaging position.

18. In a circuit breaker, a support having a fixed contact thereon, arotor journaled on the support having a contact thereon, a springcontinually urging the rotor to contact disengaging position when thecontacts are engaged, a rotatable actuator for moving the rotor tocontact engaging position, latching means for holding the rotor incontact engaging position, and an excess current actuated elementcarried by said rotor for releasing the said latching means, whereby thespring moves the rotor to contact disengaging position.

19. In a circuit breaker a support having a fixed contact thereon, arotor journaled on said support having a contact thereon, a springcontinually urging the rotor to contact disengaging position when thecontacts are engaged, a rotatable actuator for moving the rotor tocontact engaging position, means mounted on the rotor and cooperatingwith said support to hold the rotor in contact engaging position, and anexcess current actuated element carried by said rotor for releasing saidlast mentioned means whereby said spring moves said rotor in contactdisengaging position.

JAMES H. BURNSIDE, 2ND.

